Electric heater unit



A. D. KEENE 1,707,308

ELECTRIC HEATER UNIT Filed June 24, 1924 2 Sheets-Sheet April 2, 1929.

INVENTOR ATTORNEY I Zrllllllllillll .lI/Il WITNESSES:

Patented Apr. 2, 1929.

uurrso STATES trams PATENT orrics.

ALVIN D. KEENE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WEQTINCfl-IOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC HEATER UNIT.

Application filed June 24,

My invention relates to electrically heated appliances and particularly to electric heating units therefor.

i-J A ceiving the resistor wire, hold the turns in proper operative positions relatively to each other and to the solder pot. A bolt extends through all of the bars of each and serves also to support the resting unit from an annular supporting member.

In the drawings,

Figure 1 is a top plan view of a device embodying my invention, a portion being cut away to show the internal construction,

2 is a view in vertical section therethrough, and

Fig. 3 is a fragmentary sectional view of a modified form of device embodying my invention.

An electrically heated solder pot, designated generally by the numeral 11, comprises an outer substantially cylindrical casing 12 that may be made of sheet metal. A metal pct 13 is located within the casing 12 and has an upper outwardly extending flange 14c integral therewith. The rim, or outer portion of the flange, is located above the inner portion thereof in order that any solder or babbitt that is spilled thereon may flow back into the pot itself.

A relatively large annular space is provided between the outside of the solder pot proper and the inside of the casing 12. A heating unit is located adjacent to the outer surface of the solder pot and comprises a resistor member 15, of relatively heavy wire, that is preformed to comprise a double-layer open helical coil, substantially as illustrated in the figures of the drawing.

The axial length of the coil is greater than the depth of the solder pot, so that the lower turns thereof are located well below the bottom surface of the pot itself. Any suitable or desired method of constructing the doublelayer helical coil may be employed. I prefer 1924. Serial No. 722,035.

to wind each layer on a separate form, or to form the same by any suitable means, and

then to connect the lower ones thereof together, in. any manner usual in such devices. The upper ends thereof extend substantially at right angles to the turns, that is, they critend radially outwardly from the respective coils, as is more particularly shown in Fig. 1 of the drawings.

The upper ends of the heating element extend a short distance beyond. the casing 12 and are there provided with suitable connectors 16 and 17 to which the ends of suitable supply circuit conduct 's 18, only one of which shown in F 2 of the drawings, may be connected. I

A terminal box 19 is suitably secured against the casing 1.2 at the point where the upper ends of the resistor member extend through an opening 21 in the casing. A conthat member 22 extends into the bottom of the terminal bOZi 19 in order to protect the supply circuit conductors. i A plurality of sets 23, of bars 24 of refractory electric-insulating material; are pro vided, each bar having a pair of spaced grooves 25 and 26, eXten-di" laterally across the respective flat fee as thereof, substantially as illustrated in .2 of the drawings. The respective turns of the inner helices are located in the inner arcuate grooves 25, while the turns of the outer helices located in the respective outer arcuate grooves Each of the bars of refractory material provided with an opening extending laterally therethrough and numbered 2? in 2 of the drawings, through which a long red 28 extends. The rod 28 provided, at the bot: tom thereof, with a nut 29 having screw threaded engagement therewith.

At the upper end, the rod 28 extends beyond the assembled set of bars 24: and through a suitable opening 31 in a supportmg member 32 that is constituted by a substantially annular metal member fitting; loosely around the body of the solder pot inimediately below the flange portion 14 there of. A refractory washer 33 is located in the opening 31 and the red 28 extends therethrough in order to insure that it shall be electrically insulated from the metal supporting plate 32. A second nut 34- is provided at the upper end of the rod 28 whereby the bars of refractory insulating material ill) outer layer of the helically wound resistor member and the inside of the casing. I have illustrated these blocks 35. as being substantially rectangular in contour in order to permit ot the use of a relatively simple form of block, thatmay be purchased in the open market. If desired, or it necessary, special blocks of wedge shape, may be employed which will fill all of the space between the outer rasing 12 and the helically wound resistor member.

The annular supporting member or plate is bolted against the flange 14; by a plurality of relatively heavy'machine screws 36, that operatively engage a stitl'ening web 37, a plurality of such webs being provided, and a corresponding plurality of machine screws 36 being employed to suitably clamp the supporting plate against the flange of the solder pot.

It desired, a block 38, ot' heat-insulating material and otsubstantially circular contour, is located adjacent to the bottom of the casing 12 and is-supported therein by a suitable bottom plate 39, which, in turn, may be supported by a pluralityof spaced lugs 41,.

riveted. to the casing at the bottom portion thereof. The upper end of the casing 12 may be secured to the flange 14 by suitable machine bolts a2. that opera-tively engage the outer end 01 the respective stitl'ening Wedges 37.

It desired, the supporting plate 32 may be supported by machine screws Q26! projecting through the casing 12 and into the outer peripheral portion of the member 82in a manner substantially similar to the machine screws 42. Whereas, with the hereinbefore described construction as illustrated in Fig. 2 of the drawings, the heating element is removable from the casing with the pot, the latter construction above mentioned and shown in Fig. 3 would permit ofremovingthe pot while. leaving the heating unit in its proper operative position within the casing and particularly within the heat-insulating means hereinbetore described.

As it is highly desirable in devices of this kind to be able to regulate the temperature,

I provide a projecting ,tube 43 for receiving a suitable thermostat orthermometer, which tube extends into the pot and is supported therein by a suitable supporting member 44, that is bolted against the upper beveled surface of the flange portion 14.

The device embodying my invention thus provides a relatively simple and high-capac ity heating unit comprising a preformed resistor member in the shape of a double layer open helical coil, the turns of which are pre- "ventedlrom both lateral andlongitudinal movements relatively to each other by grooved reit'ractory bars that are mounted on an elongated rod which, in turn, is employed to support the entire heating unit from a supporting plate. The refractory bars hereinbefore mentioned are also etl'ective to maintain the coiled resistor member in proper operative position relatively to the outersurface of the babbit-t or solder pot. By employing two substantially similar coils and connecting them at the bottom'ends, I obtain a substantially non-iinlucti've resistor coil.

Various modifications and changes may be made without departing from the spirit and scope of the iiwention, and I desire, therefore, that only such lin'iitations shall be placed thereon as are imposed by the prior art.

I claim as my invention In a heating unit for an electrically heated appliance, in con'ibination, a resistormember preformed into a double-layer openhelical ('OIl, a pmrality oi sets of laterally-grooved refractory n'iembers tor holding said coilin proper operative osition around an-applt anee and torq n'eventing both lateral and longitudinal movements of the turns of-said coil, :1 single means extending through all ot the refractory members of a set tor-holding them in proper-operative positions relatively-to each other auditor supporting saidcoihan-d refractory members from an appliance.

In testimony whereot; Ihave hereunto subscribed my name this 16th day ofJun'e, 1924.

ALVIN D. KEEN-E. 

